The present invention relates to a shaft of a catheter system for performing intravascular procedures, more particularly to a shaft having excellent flexibility and ability for transmission of torque or force to manipulate the catheter system.
A catheter system or catheter for percutaneous transluminal coronary angioplasty (PTCA), angiography, perfusion, drug delivery or the like is introduced into a body of a patient. The catheter system includes a head portion, a shaft and a handle. When the catheter system is used, the shaft is pushed into a vessel, such as a blood vessel, from the head portion, so that the head portion is located in a desired position away from an entrance thereof by manipulating the handle.
A conventional shaft of the catheter system is formed of a single lumen in a form of a tube or wire. Often, the shaft is required to be stiff to transmit large force or torque for passing through a constricted portion of a blood vessel. Therefore, the lumen or shaft is made stiff. However, the stiff shaft tends to kink when it is manipulated since the single lumen is not enough to hold or support the force required for passing through the constricted portion. The term "kink" used herein means "crash and bend".
In order to solve the above problem, there has been proposed a shaft for a multi-lumen catheter system comprising at least two coaxial lumens, or a combination of one lumen and a stiff wire provided inside the lumen. However, when the multi-lumen catheter is manipulated, the stiff wire or the inner lumen is not positioned in a center of the multi- lumens. Therefore, one side portion of the multi-lumen catheter which contacts the stiff wire is liable to be damaged or kinked thereat. Further, although the stiff wire provided in the multi-lumens prevents the shaft from being kinked, a certain kind of catheter, such as Over The Wire PTCA catheter, does not have enough space to accommodate the stiff wire therein.
The invention has been made to obviate the foregoing difficulties, and an object of the invention is to provide a shaft for a catheter system, which is flexible and has sufficient stiffness to be manipulated easily without being kinked.
Another object of the invention is to provide a shaft for a catheter system as stated above, wherein an inner lumen or shaft can be easily assembled with an outer lumen.
A further object of the invention is to provide a shaft for a catheter system as stated above, wherein the inner lumen or shaft can be located in a center of the outer lumen.
Further objects and advantages of the invention will be apparent from the following description of the invention.